Driveway sinking & cracking help needed, please?

Question

What will cause a drive way to sink and crack like the driveway in this picture?
When having it repaired what should be done to insure that it does not sink and crack again.
This driveway as can be seen in the pictures is severely sloping away from the house and toward the neighboring house.
The concrete is pulling away from the side of this house, near the house, where the black sealer has been applied
 This house and adjacent driveway are 58 years old, and is located in Allen Park MI.
The pictures can be seen here:

http://www.flickr.com/photos/55999039@N04/
 
Thanks In Advance,
Uni